Improving water efficiency is a growing challenge for the Common Agricultural Policy. In this article, we test whether social comparison nudges can promote water-saving behavior among farmers. We report on a pilot Randomized Controlled Trial, in which information on individual and group water consumption were sent every week to farmers equipped with smartmeters. We do not detect an effect of nudges on average water consumption. We however find that the nudge decreases water consumption at the top of the distribution while it increases consumption at the bottom. This study highlights the potential of nudges as an agricultural policy tool.